sys/dev/drm/include/linux/compiler.h

   1 /*-
   2  * Copyright (c) 2010 Isilon Systems, Inc.
   3  * Copyright (c) 2010 iX Systems, Inc.
   4  * Copyright (c) 2010 Panasas, Inc.
   5  * Copyright (c) 2013-2016 Mellanox Technologies, Ltd.
   6  * Copyright (c) 2015-2018 François Tigeot <ftigeot@wolfpond.org>
   7  * All rights reserved.
   8  *
   9  * Redistribution and use in source and binary forms, with or without
  10  * modification, are permitted provided that the following conditions
  11  * are met:
  12  * 1. Redistributions of source code must retain the above copyright
  13  *    notice unmodified, this list of conditions, and the following
  14  *    disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  20  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  21  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  22  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  23  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  24  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  25  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  26  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  27  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  28  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  29  */
  30
  31 #ifndef _LINUX_COMPILER_H_
  32 #define _LINUX_COMPILER_H_
  33
  34 #include <sys/cdefs.h>
  35
  36 #define __user
  37 #define __kernel
  38 #define __safe
  39 #define __force
  40 #define __nocast
  41 #define __iomem
  42 #define __chk_user_ptr(x)               0
  43 #define __chk_io_ptr(x)                 0
  44 #define __builtin_warning(x, y...)      (1)
  45 #define __acquires(x)
  46 #define __releases(x)
  47 #define __acquire(x)                    0
  48 #define __release(x)                    0
  49 #define __cond_lock(x,c)                (c)
  50 #define __bitwise
  51 #define __devinitdata
  52 #define __init
  53 #define __devinit
  54 #define __devexit
  55 #define __exit
  56 #define __stringify(x)                  #x
  57 #define __attribute_const__             __attribute__((__const__))
  58 #undef __always_inline
  59 #define __always_inline                 inline
  60
  61 #define likely(x)                       __builtin_expect(!!(x), 1)
  62 #define unlikely(x)                     __builtin_expect(!!(x), 0)
  63 #define typeof(x)                       __typeof(x)
  64
  65 #define __read_mostly
  66 #define __always_unused                 __unused
  67 #define __must_check                    __heedresult
  68
  69 #define __printf(a,b)                   __printflike(a,b)
  70
  71
  72 #define barrier()       cpu_ccfence()
  73
  74 #define ACCESS_ONCE(x)  (*(volatile typeof(x) *)&(x))
  75
  76 #ifdef _KERNEL          /* This file is included by kdump(1) */
  77
  78 #include <sys/param.h>
  79
  80 /*
  81  * The READ_ONCE() and WRITE_ONCE() macros force volatile accesses to
  82  * various data types.
  83  * Their complexity is caused by the necessity to work-around
  84  * compiler cleverness and bugs.
  85  * Some GCC versions drop the volatile modifier if the variable used
  86  * is not of a scalar type.
  87  */
  88 static inline void
  89 __volatile_read(const volatile void *x, int size, void *result)
  90 {
  91         switch(size) {
  92         case 8:
  93                 *(uint64_t *)result = *(const volatile uint64_t *)x;
  94                 break;
  95         case 4:
  96                 *(uint32_t *)result = *(const volatile uint32_t *)x;
  97                 break;
  98         case 2:
  99                 *(uint16_t *)result = *(const volatile uint16_t *)x;
 100                 break;
 101         case 1:
 102                 *(uint8_t *)result = *(const volatile uint8_t *)x;
 103                 break;
 104         default:
 105                 panic("__volatile_read called with size %d\n", size);
 106         }
 107 }
 108
 109 static inline void
 110 __volatile_write(volatile void *var, int size, void *value)
 111 {
 112         switch(size) {
 113         case 8:
 114                 *(volatile uint64_t *)var = *(uint64_t *)value;
 115                 break;
 116         case 4:
 117                 *(volatile uint32_t *)var = *(uint32_t *)value;
 118                 break;
 119         case 2:
 120                 *(volatile uint16_t *)var = *(uint16_t *)value;
 121                 break;
 122         case 1:
 123                 *(volatile uint8_t *)var = *(uint8_t *)value;
 124                 break;
 125         default:
 126                 panic("__volatile_write called with size %d\n", size);
 127         }
 128
 129 }
 130
 131 #define READ_ONCE(x) ({                                         \
 132         union {                                                 \
 133                 __typeof(x) initial_type;                       \
 134                 uint8_t nc_type;                                \
 135         } result;                                               \
 136                                                                 \
 137         result.nc_type = 0;                                     \
 138         __volatile_read(&(x), sizeof(x), &result.nc_type);      \
 139         result.initial_type;                                    \
 140 })
 141
 142 #define WRITE_ONCE(var, value) ({                               \
 143         union {                                                 \
 144                 __typeof(var) initial_type;                     \
 145                 uint8_t nc_type;                                \
 146         } result;                                               \
 147                                                                 \
 148         result.initial_type = value;                            \
 149         __volatile_write(&(var), sizeof(var), &result.nc_type); \
 150         result.initial_type;                                    \
 151 })
 152
 153 #endif  /* __KERNEL__ */
 154
 155 #endif  /* _LINUX_COMPILER_H_ */